Sunday, June 4, 2017

Cold Hardy Osteospermums

These South African daisies are commonly grown as tender annuals in the northern states, but there are cold hardy species and selections. "Avalanche" is a particularly good one worth tracking down. I suspect it is a white selection of the normally lavender pink O. jucundum. I have both in the gardens now and although the jucundums did suffer a bit this winter, oddly since it was milder than last winter, they are back in bloom along with the 'Avalanche". They will produce seeds if multiple clones are present, and both are easy to propagate by severing and replanting pieces from the stems that root as they grow outwards. I usually put some coarse sand over some of the stems as temperatures drop and sometimes cover them lightly with wood chips to minimize dieback during cold winters. If the stems survive they resprout quickly when spring arrives. They bloom throughout the growing season but are especially spectacular right now. I think the very mild and rather strange winter, with arguably the worst weather in March (!) was to their liking so they are making lots of flowers right now.

Seeds of Osteospermum come in two types, one somewhat triangular and nut like, and a flatter rounded seed. The latter is probably primed for faster germination whereas the other is supposed to remain viable for longer, so the plant hedges its survival strategy by having two different types of seeds. However I havent really noticed much difference in germination of either, if anything the first type of seed seems to be viable more often than the flatter ones. I should get a good seed crop from the area where both jucundum and "Avalanche" grow together, but "Avalanche" alone rarely sets seeds.

About Me

I'm a high school biology teacher with a passionate interest in plants for as long as I can remember. I have two horticulture degrees, BS and Ph.D. from Cornell and I've worked at the New York Botanical Garden in the past. My plant interests are quite simple: everything! Still, I have a special affection for South African plants, including, of course, pelargoniums (aka "geraniums").